> i am not familier with C language and i have already told you that i have just started progrmmimng on microcontrollers so please keep in mind MY LEVEL.

You specifically asked a question and posted code, everything is fine!

(The slightly inflamatory subject I had chosen was because I reacted on the part where you seemed to require an implementation "ASSEMBLER" and within that implementation further implementation details (ajmp/acall) while I felt you were talking about algorithms)

Anyway here goes assembler code, how about:

   000A                     342 00102$:
   000A 7A 00               343         mov     r2,#0x00
   000C                     344 00115$:
   000C EA                  345         mov     a,r2
   000D 20 E7 FA            346         jb      acc.7,00102$
   0010 7B 80               347         mov     r3,#0x80
   0012                     348 00111$:
   0012 EB                  349         mov     a,r3
   0013 60 13               350         jz      00117$
   0015 EA                  351         mov     a,r2
   0016 4B                  352         orl     a,r3
   0017 F5 90               353         mov     _P1,a
   0019 7C BE               354         mov     r4,#0xBE
   001B 7D AF               355         mov     r5,#0xAF
   001D                     356 00104$:
   001D 00                  357          NOP 
   001E DC FD               358         djnz    r4,00104$
   0020 DD FB               359         djnz    r5,00104$
   0022 EB                  360         mov     a,r3
   0023 C3                  361         clr     c
   0024 13                  362         rrc     a
   0025 FB                  363         mov     r3,a
   0026 80 EA               364         sjmp    00111$
   0028                     365 00117$:
   0028 EA                  366         mov     a,r2
   0029 2A                  367         add     a,r2
   002A FA                  368         mov     r2,a
   002B 43 02 01            369         orl     ar2,#0x01
   002E 80 DC               370         sjmp    00115$

 

Which was generated from:

#include <8051.h>

static inline void delay(void)
{
  unsigned char i = 0xbe;       // 0x00 -> 256
  unsigned char k = 0xaf;       // 0x00 -> 256

  do
  { 
    do
    { 
      __asm NOP __endasm;
    } while ( --i );
  } while( --k );
}


void main(void)
{
  while( 2 )
  {
    unsigned char sanddrop;     // highest bit on top
    unsigned char sandbottom;   // lowest bit at bottom
    for( sandbottom = 0x00; !(sandbottom & 0x80); sandbottom <<= 1, sandbottom |= 0x01 ) // C is ugly too!
    {
      for( sanddrop = 0x80; sanddrop; sanddrop >>= 1 )
      {
        P1 = sanddrop | sandbottom;
        delay();
      }
    }  
  }  
}
 

with:
sdcc --no-xinit-opt --main-return --acall-ajmp --std-sdcc99 --no-c-code-in-asm sandwatch.c

(Note, the table approach Michael mentioned makes a lot of sense too)